Answer:
Step-by-step explanation:
Given that a researcher is planning to construct a one-sample z ‑confidence interval for a population mean
The confidence interval would be calculated as
Here margin of error = Z critical * std error determines the size of the confidence interval
Margin of error dependds on i) Z critical value ii) std deviation
iii) Inversely to square root of sample size.
Hence margin of error would be small if
.B) The researcher increases the sample size
C) The researcher lowers the confidence level
E) The population standard deviation turns out to be lower than expected.